Braking apparatus



April 14, 1936. I w .0 vr- 2,037,432

BRAKING APPARATUS Filed Dec. 51, 1931 2 Sheets-Sheet 1 17 J+ 75 24 d2 .50

j g0lz'der J59 97746442 April 4, 1936. w. FQOLIV-ER 2,037,432

BRAKING APPARATUS Filed Dec. 31, 1931 2 Sheets-Sheet 2 T Z4 g5 77 1; NA 21L 1 21' I g 4 ixwx\i 7/ away M216 9 )7/CCL12ZQM.

Patented Apr. 14, '1936 Wallace F.

Oliver, Detroit, Mich, assignor to Hydraulic Brake Company, Detroit, Micln, a corporation of California Application December 31, 1931, Serial No. 584,037 4 Claims. .(Cl.188-79.5)

My invention relates to braking apparatus and is particularly desirable for use in connection with the braking apparatus of automobiles and other motor vehicles, although it may also be applied to other uses. The present tendency in automobiles is to increase the weight and speed of the vehicle, while at the same time there is an insistent demand to decrease the effort necessary V to handle such vehicles under all conditions, and also to decrease the amount of work required to maintain thesevehicles in proper operating condition. I

An object of my invention efficient brake. system which will give increased braking effect without requiring the driver of the vehicle to exert increased effort on the operating controls.

Another object. of this invention is to .provide a braking system which may easily be adjusted and maintained at a state of maximum efliciency.

Another object is to provide a braking system having the foregoing features which is economical to manufacture, has a minimum number of parts, and is durable and absolutely reliable. in service. I

Other objects and advantages will become apparent as the description proceeds.

Referring to the drawings: Figure-1 is a vertical elevation partly in section showing my invention applied to-the wheel brake mechanism of an automobile; I Fig. 2 is an enlarged view of the left-hand end ofthe cylinder mechanism shown in Fig. 1 but showing a slightly difierent type of boot from that shown in Fig. 1;

Figs. 3 and 4 are viewssimilar to Fig. 2 but showing modifications of the structure shown in F 2;

Fig. 5 is a vertical section taken on the line 55 of Fi 1; and

Fig. 6 is a horizontal section showing the de' tail taken on the line 9-9 of Fig. 1.

Referring to the embodiment shown in Figs. 1, 2, 5, and 6, I have illustrated my invention as applied to the wheel brake mechanism of an automobile, which consists in general of a brakedrum 1 suitably secured to the vehicle wheel by any well known means, and an axle housing 9 to which is secured a pan 9 which cooperates with the brake drum 1 to provide an enclosure in which are located the operating parts of the brake mechanism. Supporting pins it are attached to the pan 9 and carry brake shoes II and I2 which are normally located in the positions shown but which are capable of movement into engageis to provide a more and rotate the annulus 2| thereby moving the ment with the brake drum I by mechanism which will be described hereinafter. The pan 9 also supports guides l9 which guide the brake shoes i II and I2 during their movement to and from active and inactive position. 5 A motor cylinder I4 is suitably attached to the pan 9 between the free ends of the brake shoes II and I2. This motor cylinder is of uniform bore throughout and-is provided with opposedpstons l5 and I6 which are operated to move the brake shoes II and I2 into braking engagement with the drum 1 when fluid under pressure is forced into the cylinder l4 bysuitable fluid compressing means and conduits which may be, of the type disclosed in United States Patent No. 15 1,758,671, or which may be of any other suitable or desirable type. The piston I5 is directly connected with the brake shoe |2 by a piston rod H which has one end rounded to fit into a socket formed in the rear side of the piston l5 and which 20 forms a separable connection therewith. The other end of the piston rod I1 is provided with a slot l8 into which projects the roundedend I9 of the brake shoe I2. The engagement of the end l9 in the slot It prevents rotation of the piston rod H. The piston rod I1 is enlarged adjacent the slot I8 and is provided with threads 29 which engage with the corresponding threads formed on the inner surface of an annulus 2|. Theanmally rests against the'adjacent end of the cylinder I4 and'forms a stop for limiting the inward movement of the brake shoe |2 under the action of its retractile spring 23. The periphery of the flange 22 is serrated as best shown in Fig. 5 and the adjacent portion of the pan 9 is provided with a suitable opening 2| through which a screw driver or other similar tool may be inserted to engage the serrations on the flange 22 piston rod H to adjust the normal position of the brake shoe 2. The piston 4 l carries a spring clip 25 which engages the serrations in' the periphery of the flange 22 and holds the annulus 2| against rotation except when a tool is inserted for the purpose of adjusting the position of the brake shoes. A boot 26 of rubber or other suitable material excludes dust and moisture from the joint formed between the cylinder I4 and the annulus 2| and thereby cooperates with the annulus 2| and piston rod II in excluding dirt and'moisture from that part of the cylinder which is in rear of the piston It.

when the vehicleia moving in the forward direction the brake drum l rotates in the direc 6 tion of the arrow 2'! so that the brake shoe II is eiiect is created by the iorward shoe. In order to increase the effectiveness of the bramng apparatus without increasing the pedal pressure which the operator must exert I increme the force which is exerted on the forward shoe and thereby greatly increase the efllciency o! the braking apparatus. I accomplish this by interposing a lever 28 pivoted to the pan 9 by pin 29 between the brake shoe I I and the piston rod 30, which is pivoted to the upper end of the lever 28 by a pin 3i or any other suitable connection. The pin 3i prevents rotation 01' the piston rod is so that the of! position of the brake shoe H can be adjusted by inserting a screw driver through an opening in the pan 9 and turning the annular member 32 in a manner similar to that used in adjusting the oil position of the brake shoe i2.

At the point where the lever 28 contacts with the end of the brake shoe II the lever is provided with a boss 33 which in the present embodiment is located midway between the pins 29 and 3! so that twice as much force is exerted on the brake shoe H as on the brake shoe i2. One end 01' the retractile spring 23 is connected to a link 34 which in turn is connected to the brake shoe H. Under some conditions it is found desirable to have this link rest against the side of and form a guide for the lever 28 to prevent vibration and rattling of this lever when the machine is traveling over a rough road. I The retractile spring 23 must be 01' suiilcient strength to return the brake shoes to off position and also to return the piston IS with sufllcient force to drive the fluid from the cylinder 54 back through the conduits and past the return valve which is commonly associated with the discharge end of the fluid compressor. Such a return valve is indicated by reference numeral 25 in Loughead Patent No.

1,847,402, dated March 1, 1932.

' In Fig. 3 of the drawings I have illustrated a slightly different means tor sealing the end of the cylinder It. In this embodiment the adjusting annulus 2i for the piston rod I1 is provided with threaded openings into which are screwed bolts 40 whichsecure flexible boots 26' to the flange 22' or the annular member 2|. The other parts shown in this figure are identical with the similar parts of Fig. 2.

In Fig. 4 the piston rod I1" is not threaded but has an enlarged portion 4! which provides a shoulder 42 which normally rests against the end 33 of a recess formed in the annular member 2|" which in turn is threaded at 44 to the end of the cylinder iii". In this embodiment no boot is necessary since the threaded engagement between the end oi the cylinder I4" and the annular member- 2l" provides a sumcient seal to exclude dirt and moisture. In this embodiment it is not necessary that the piston rod ll" be held against rotation.

Having thus described several embodiments of my invention I wish it to be understood that my invention is capable of being incorporated in various iorms and that the scope oi. my invention is to be limited solely by the following claims.

I claim:

1. In mechanism of the class described, the

combination 01' a fluid cylinder, a piston reciprocably mounted therein, a piston rod separably connected to said piston, said cylinder having an end, a member threadedly connected with said piston rod and normally engaging said end to limit inward movement of said piston rod, braking means preventing rotation of said piston rod, resilient means normally preventing rotation of said member, and sealing means connecting said member and cylinder.

2. In mechanism of the class described, the combination of a fluid cylinder, a piston reciprocable therein, a piston rod ior said piston, said rod having a shoulder, and a member directly engageable with said shoulder and threadedly connected with said cylinder whereby adjustment of said threaded connection varies the permissible movement of said rod in one direction.

3. In mechanism oi the class described, the

combination of a brake drum, a supporting pan closing the open end of said drum, a brake element mounted on said pan and adapted to engage said drum, a member mounted on said pan and forming a iiuid cylinder, a piston reciprocable therein,.a second member constituting a piston rod, said second member having one end engaging said element and another end directly engaging said piston, a spring for holding said piston against said last-mentioned end. an annulus interposed between said members for limiting relative movement therebetween in one direction only, said annulus having an adjustable threaded connection with one oi-said members and a shoulder for limiting movement in one direction between said annulus and the other member, and means whereby said threaded connection may he manually adjusted without disassembly of said drum and pan.

4. In mechanism of the class described, the combination of a brake drum, a brake shoe engageable therewith, a pan supporting said shoe, a fluid cylinder for applying said shoe against said drum, a piston in said cylinder, a piston rod having one end in direct abutting engagement with said piston and another end engaging said shoe, a member adjustably interposed between said rod and an end of said cylinder to limit movement of said rod in one direction, a spring urging said piston against said rod, means for adjusting said rod from the exterior 01' said pan, and a spring. carried by said cylinder for locking said member in adjusted position.

WALLACE F. OLIVE. 

